Our basic aim is to learn what the molecular basis for reaction selectivity is for Vitamin B-6. More specifically, we want to find out how a particular enzyme can cause vitamin B-6 to catalyze one particular reaction while a different enzyme can cause vitamin B-6 to catalyze an entirely different reaction of the same substrate. In doing this, we seek a semiquantitative measure of the steriochemical factors which lead to this kind of reaction selectivity. The specific aims of our individual parts of the project are: 1. To carry out a number of detailed kinetic studies on the metal catalyzed elimination of electronegative groups from amino acids and on their racemization reactions. This will show whether these reactions are controlled by the stereochemistry of the schiff base or of the DHP and give a semiquantitative measure of the rate dependence on conformation. 2. Using kinetically inert cobalt (III) and rhodium(III) complxes the rate of reaction of the different diesteroisomers will be studied to learn how reactivity depends on the different orientations with respect to the azomethine system and give a semiquantitative measure of this effect. 3. The effects of molecular complex formation involving partial charge withdrawal or donation will be investigated. Structures will be determined by nmr and compared to rate data, the object being to try to separate the effects due to orientation from the effects due to system perturbation. BIBLIOGRAPHIC REFERENCE: "Carbon-13 Nuclear Magnetic Resonance Spectra of the Vitamin B-6 Group." T.H. Witherup, J. Org. Chem. 40, 2229 (1975).